This research grant proposal plans experiments on three projects involving enzymatic activation mechanisms. Specifically, the project hopes to: 1. Establish the molecular mechanism for the activation of crystalline pyruvate oxidase by phospholipids. 2. Compare phospholipid activated oxidase with trypsin activated oxidase. 3. Determine the mechanism of activation of endonuclease I by colicin E2. 4. Characterize the active site and the amino acid residues at the heme binding site of chloroperoxidase which are responsible for the P-450 character of this enzyme. 5. Examine the relationship between chloroperoxidase compound I and the P-450 hydroxylating intermediate.